Portable oxygen concentrators are commonly used in the home medical market to treat ambulatory patients with chronic obstructive pulmonary diseases. To make an oxygen concentrator portable, the oxygen concentrator must be as small as possible and weigh as little as possible while delivering sufficient concentrated oxygen gas flow to the ambulatory patient.
Compressors are used in oxygen concentrators to supply high-pressure feed air to a Pressure Swing Adsorption (PSA) Module or concentrator. Air compressors, especially rotary piston air compressors and diaphragm-type air compressors, produce a significant amount of vibration during use. The vibration produced by these types of compressors is primarily torsional due to the compressor motor slowing down as the air pressure builds during an upstroke of a compressor cycle and then the compressor motor speeding up as the cylinder refills. Also, if the compressor includes more than one cylinder, a torsional mode of vibration perpendicular to the motor axis may also be created by the fact that the axes of the additional cylinders are not generally in the same plane.
To isolate the compressor and reduce the transmitted vibration, low-rate springs with a large amount of travel have been used, but this increases the amount of space that the compressor installation requires to allow for the compressor to move. This larger amount of space required for the compressor isolation makes the portable oxygen concentrator larger. Also, the compressor may knock against the interior of a compressor housing, particularly when it starts, stops or is moved, which creates excessive noise and possible damage or wear to the compressor and hoses.